Boiler-furnace.



Unrrnn States PATENT OFFICE.-

WILLIAM KNEEN, OF LONDON, ENGLAND.

BOILER-FURNACE.

SPECIFICATION forming part of Letters Patent No. 663,576, dated December 11, 1900.

Application filed August 7,1900- Serial N0. 26,182. (NO model.)

My invention relates to furnaces in which air is conducted, by means of pipes, into the gases from the furnace near to and behind the fire-bridge.

My present invention is in the nature of an improvement upon the furnace forming the subject of my Patent No. 505,561, dated Sep tember 26, 1893.

Spaces of about three and a half inches are provided between the pipes, through which spaces the gases pass, and there are apertures in each pipe through which the air passes into the gases, so that the said air iningles with the gases which pass between the pipes. I arrange the air-supply pipes so as to conduct some of the air as high up into the furnace as possible, and I construct in proximity to the said pipes, either behind or in front thereof, a hanging bridge or arch of firebricks with a space of about two inches between the said arch and the air-pipes. The air-apertures in the pipes are arranged so as to cause jets of air to be directed toward the arch. The pipes when in position and viewed from the furnace-door appear as though they overlap the arch. By these meansthe hot light gases which otherwise would pass along against the top plate or crown of the boilerfurnace are compelled by the hanging bridge or arch to pass downward for a few inches,

and owing to the said arch being in close proximity to the apertures where the air is liberated and owing to the pipes lapping the arch the gases at this point are met by jets of air between the arch and the pipes and aconsiderably improved combustion is obtained. The aforesaid air-pipes are subjected to severe strains owing to the great changes in temperature to which they are subjected, and I so construct the said air-pipes as to render them capable of withstanding these durable. This I efiect by building up the said air-pipes of superposed sections, as hereinafter described, the said sectional construction preventing the disintegration of the pipes under the changes of temperature to which they are subjected.

Figure 1 of the accompanying drawings is a longitudinal vertical section of a portion of a boiler-furnace provided with my improvements, and Fig. 2 is a horizontal section of the same. Fig. 3 shows in section and plan a portion of one of the'air-pipes drawn to a larger scale, and Fig. 4 illustrates a modification.

A represents the fire-bars, B the ash-pit, and C an ordinary bridge at the back of the furnace. Behind the bridge 0 is a chamber D, into which air is conducted by a pipe or pipes E, situated in the ash-pit B, which air may be forced through the pipe or pipes E into the chamber D by means of steam-jets or other suitable means. Projecting upward from and communicating with the interior of the chamber D are the air-pipes F, each pipe having two rows of perforations f, through which the air forced into the chamber D passes in the form of jets. The pipes F are arranged at distances apart of, say, about three and a half inches, so as to leave spaces between adjacent pipes and between the end pipes and the wall of the furnace, through which spaces the smoke and heated gases from the furnace pass on their Way to the chimney, the air issuing through the perforations f mingling with the said smoke and gases, whereby their practically-perfect combustion is effected. The said pipes Fare built up in superposed sections f say about two inches in height and preferably made of thick fireclay of elongated transverse section, as shown in Figs. 2, 3, and 4, with the end of the sectional figure nearest the furnace proper somewhat cone-shaped or cigar-shaped and with the'other end of the sectional figure rounded. The sections may be held together by making holes f in the upper and lower plastic fire-clay between the sections, which.

clay, when the sections are pressed together, enters the holes and retains the sections in place, or the upper and lower faces of the strains, so that the said air-pipes are very 1 sections may have ribs or projections and grooves or recesses, as shown in Fig. 4, to em gage together,and there may be left sufficient play between these ribs or projections and grooves or recesses to allow of relative movement of the sections under variations of temperature.

Behindthe pipes F, at a distance therefrom of, say, about two inches, is a fire-brick arch G, which depends below the upper ends of the pipes F, so that the air issuing through the certained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is- 1. The combination with the fire-bridge of a furnace of upwardly-projecting perforated air-pipes (with spaces between them) behind the fire-bridge the said air-pipes being constructed of a series of short superposed sections as described; means for forcing airin to the said pipes and through the perforations therein and a depending arch in proximity to the upper ends of the said air-pipes against which arch the air coming through the upper perforations in the said air-pipes is caused to impinge together with the gases and smoke from the furnace, substantially as hereinbefore described.

2. The combination of the fire-bridge of a furnace of upwardly-projecting perforated air-pipes (with spaces between them) behind the fire-bridge, the said air-pipes being constructed of a series of short superposed sections, the end of the section nearest the fireplace being cone-shaped and the other end in which are the perforations being rounded.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

WILLIAM KNEEN. WVitnesses:

JOHN EDWARD NEWTON,

PERCY READ GOLDRING. 

